INTER-STRAIN RELATIONSHIPS AMONG WINE LEUCONOSTOCS AND THEIR DIVERGENCE FROM OTHER LEUCONOSTOC SPECIES, AS REVEALED BY LOW-FREQUENCY RESTRICTION FRAGMENT ANALYSIS OF GENOMIC DNA

Thirty Leuconostoc oenos strains, representing 28 different isolates, were distributed into 20 genomic groups according to PFGE patterns of restriction digests. The 8 bp-specific enzymes Sfi I, Not I and Asc I cleaved the Leuc. oenos DNA in a mean of 17, 11 and four fragments res pectively and Sma I produced more than 50 fragments per genome. The st rain differentiating capacity of the four enzymes was similar; only tw o related genomic groups failed to be distinguished by Ase I or Not I. Genomic relationships between Leuc. oenos strains were quantified by numerical analysis of Not I and Sfi I banding patterns. More than half of the strains, including the starters ML34 and PSU-1, formed a major cluster. The average size of the Leuc. oenos genome was estimated as 1.86 Mb. Although similar values were obtained for the genomes of Leus . mesenteroides, Leuc. pseudomesenteroides, Leuc. gelidum and Leuc. ci treum, a significant divergence between wine and non-wine species was inferred from comparisons of genome cleavage frequencies, determined w ith five different enzymes.